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| Illustration by Holland and Foley Building Design. |
A Real-World Example of Sustainable Building
By Sarah Holland and David Foley
Holland & Foley Building Design
232 Beech Hill Rd., Northport, Maine 04849
(207) 338-9869
If you have visited the new home of The Maine Organic Farmers and Gardeners Association in Unity, you may have seen a large building in the northeast corner of the site. Clad in shingles and clapboards, painted yellow, white and barn red, the Common Ground Center fits in with traditional farm buildings in the area – but the building looks forward, not backward, pointing the way to a sustainable future.
When MOFGA first hired us to design its new headquarters, we knew that the organization wanted to pay homage to traditional buildings and demonstrate new possibilities in environmentally responsible architecture. The project also had to meet several other tough challenges.
Because MOFGA operates within tight budgets and schedules, creating its new permanent home strained its resources. The Common Ground Center had to be built quickly and at a cost comparable to or less than that for “normal” commercial buildings. The building has to support many kinds of activities, so its spaces have to be flexible enough for many uses. For several hectic days each year, the building serves as the Exhibition Hall and operations base for the Common Ground Fair, but the same spaces have to serve other conferences and meetings, support a commercial kitchen suitable for catering, classes and demonstrations, house a growing library of agricultural books and pamphlets, and provide offices for MOFGA staff. The building needs to be adaptable to future needs and opportunities. And, of course, the building had to meet federal, state and local codes for safety, accessibility and health.
Effective Environmental Building Strategies
No single building can use every “Green” product or system – instead, priorities must be set. Just as the gas mileage of one’s car has more impact on the environment than the choice of “paper or plastic” at the market, certain environmental building strategies yield greater results than others do. Our experience has taught us to focus on the following principles:
• Conserve Energy – Heating, cooling and lighting buildings consume vast quantities of energy, at great cost to the economy and to the planet. A more sensible approach is to let insulation replace tanker spills, sunshine replace offshore drilling, and efficient lights replace plutonium.
• Avoid Natural Habitat Destruction – The destruction of natural ecosystems and loss of biodiversity is one of Earth’s most critical environmental problems and is directly linked to settlement patterns and the resources we dig up or cut down for our use. We’re beginning to be more intelligent: We’re planning our towns and neighborhoods, and materials are becoming more efficient, better engineered, available from “well-managed” sources, and designed for reuse or recycling at the end of their lives.
• Provide a Healthy Environment – Being indoors should not make you sick, yet the Environmental Protection Agency estimates that 11,400 people in the United States die each year from indoor air pollution. Environmentalism “begins at home:” Buildings must provide good indoor air quality, comfortable temperatures and humidity, good lighting, and good acoustics.
Siting and Layout
Our design began with the building site, which MOFGA had chosen during a months-long planning effort. We oriented the building so that the spaces most often used by people are to the south, with storage, utilities, and seldom-occupied spaces to the north. The shape of the building creates a south-facing outdoor courtyard that offers a sunny, sheltered spot for outdoor lunches and meetings. North, east and west entrances are protected by porches and roof overhangs. The Office Wing has a two-story, south-facing atrium, to bring solar heat and natural daylight deep into the interior.
We designed a large area of south-facing roof in the Central wing of the building, at the right pitch for mounting solar collectors in the future. MOFGA’s long-term goal is to let the sun help heat the air and generate electricity.
A Snug, Well-Insulated Structure
We designed a heavy insulation system for spaces used daily: seven inches of dense-packed cellulose (made from recycled paper) in the walls and 14 inches in the roof. The main entry to the Office Wing is a vestibule with two pairs of doors, acting as an “airlock.”
The Exhibition Hall wing is a timber-framed structure. Modern timber frames are usually clad with structural insulating panels (SIPs), a “sandwich” of oriented-strand board and foam insulation. We specified 6-inch panels for the walls and 8-inch panels for the roof. We chose expanded polystyrene foam for the insulation, because it uses no chlorinated fluorocarbons (CFCs) and is a healthier choice than alternative foams.
Windows have a huge impact on energy performance in buildings. We chose “Thermotech” windows from Canada; they are exceptionally energy-efficient and reasonable in price. We specified high-solar-gain glass for the south windows, to maximize solar heating in the winter, and low-solar-gain glass for the east and west windows, to lessen cooling loads in the summer.
These efforts resulted in heating and cooling loads far below those of “conventional” buildings in Maine, greater comfort for the occupants, cost savings for MOFGA, and fewer stresses on the planet.
Flexible Heating
MOFGA envisions a day when its permanent home will be powered by renewable energy sources, so we.provided a heating system that is ready for renewables. With our consulting engineers, Bruce Patten and Marc Rosenbaum, we placed a 2,000-gallon, insulated water tank in the boiler room. Heat exchange coils in the hot water bath lead to radiators, fan coils and hot water spigots. Anything that can heat water can heat the Common Ground Center. While MOFGA currently uses two high-efficiency, LP gas boilers, in the future solar panels, biomass boilers or even hydrogen fuel cells can be used.
Ventilation Where and When It’s Needed
The best way to ensure good indoor air quality is to “build tight and ventilate right.” “Ventilating right” in this building takes several forms. In nice weather, operable windows can provide plenty of fresh air. At other times, the building uses heat recovery ventilators (HRVs) – clever devices that pass warm exhaust air through a heat exchanger to preheat incoming fresh air, so that adequate ventilation doesn’t require excessive energy. The Common Ground Center has from zero to 600 people in it at any time, requiring a wide range of ventilation rates. The HRVs can be set on low or high, and a carbon dioxide sensor tells the HRVs when ventilation is required, so the units run only when needed. Hot water coils in the HRVs help warm ventilation air on very cold days.
Lighting for Many Needs
We worked with lighting consultant Brian McGowan to specify state-of-the-art, high-efficiency lamps and fixtures. In the office and bathroom wings, the lights are generally used for the same purpose at all times, but the Exhibition Hall may host a flower show one weekend and a dance the next, requiring a wide range of light levels and qualities. We used dimmable compact fluorescent lights in wall sconces, and color-correct high-intensity discharge (HID) lights in overhead fixtures, allowing light levels from dim to dazzling. At 0.9 watts per square foot of building area, the lighting of the Common Ground Center is among the most efficient anywhere in North America.
Resource-Efficient Materials
Most building materials have an environmental cost. As far as possible, we used materials that keep the cost low. The interior hardwood trim and exterior shingle siding were from forests certified by Scientific Certification SystemsTM as “well-managed.” The white pine for the timber frame in the Exhibition Hall and the white cedar used for exterior porch columns came from local, family-run woodlots. When “conventional” lumber was necessary, we used resource-efficient products, such as engineered wood I-joists, glue-laminated timbers and trusses. Interior partitions are framed with light-gauge steel, a recycled content product that avoids wood use and can be recycled at the end of its life. The steel roof is also recycled-content and recyclable.
The Common Ground Center sits on a frost-protected, shallow-slab foundation. Used throughout Northern Europe and Alaska, this kind of foundation relies on drainage and rigid insulation to avoid the need for frostwalls and footings. This saves concrete, a material that requires enormous amounts of energy to produce and transport.
Designing for Time
Everyone knows that buildings are three-dimensional, but they also occupy a fourth dimension – time. Buildings have to adapt and change, or they’re torn down. The Common Ground Center can change as MOFGA’s needs change. For example, the timber frame in the Exhibition Hall can easily last 500 years, but the insulating panels, windows, lights, and such may change dozens of times. In the Office Wing, we used a column-and-beam structural system so that interior walls don’t have to carry structural loads. This allows the interior office layout to change. In commercial buildings, telephones and computers are re-cabled every five years on average. Typical office buildings use dropped ceilings or raised floors to carry electrical, telephone and data cables. Here, we designed furred-out wood baseboard chases to carry the cables. As noted above, we designed the heating system to adapt to alternative fuel sources.
What Really Matters
We’ve described the design of the Common Ground Center, and the “stuff” it’s made of, but what really matters are the people who use it and the patterns of activity that take place there. The building is a setting for conferences, seminars, classes, celebrations and the task of promoting sustainable, organic agriculture.
Building the Common Ground Center took the hard work of scores of people: Executive Director Russell Libby, Construction Manager Rene Burdet, Events Coordinator Susan Pierce, the members of MOFGA’s Building Committee, Elwin Littlefield and Richard Patterson of E.W. Littlefield and Sons Contractors, the timber-framing collaboration of Connolly and Company, R.A. Krouse, Fairbanks Frames and Mike Smiley, and many paid and volunteer laborers who worked long and hard to make a building in which everyone can take pride.
The Common Ground Center exists because MOFGA had a vision and did the hard work. Plenty of work remains to be done, and funds are still needed to complete MOFGA’s new home. We were honored to work with MOFGA, and plan to give them our continuing support. We hope you will, too.
